Exploring the Prevalence and Biological Features of Astigmatism in Primary School Children in Zibo City, China.

OBJECTIVE

To evaluate the prevalence of astigmatism and its association with ocular biometrics in primary schoolchildren in Zibo City, China.

METHODS

A cross-sectional study was conducted among 25,140 children aged 7-13 years from 19 primary schools in Linzi District, Zibo City, China, between April and May 2024. Refractive status was assessed via autorefractometry under natural pupil conditions, and astigmatism prevalence was determined using right-eye data. The study evaluated astigmatism severity (mild, moderate, or high), axis orientation (with-the-rule, against-the-rule, or oblique), visual acuity, and correlations with spherical refraction. A nested case-control analysis was performed to compare ocular biometric parameters, including axial length (AL), central corneal thickness (CCT), corneal diameter (white-to-white, WTW), and lens thickness (LT), among groups stratified by astigmatism severity.

RESULTS

The overall prevalence of astigmatism was 46.21% (95% CI: 45.6%-46.8%), increasing with advancing age and school grade. Astigmatism severity distribution was as follows: mild (37.16%), moderate (6.81%), and high (2.24%) among all participants. Among the 11,616 children with astigmatism, 62.86% had with-the-rule astigmatism, 27.48% exhibited against-the-rule astigmatism, and 9.66% presented oblique astigmatism. Visual acuity exhibited a significant decline with increasing astigmatism severity (p < 0.001). Higher astigmatism severity was inversely associated with myopia prevalence (p=0.04). Ocular biometric parameters, including AL, CCT, WTW, and LT, showed significant differences across severity groups (p < 0.05).

CONCLUSION

Astigmatism is highly prevalent among primary school children in Linzi District, with significant associations between severity, ocular biometrics, and visual outcomes. These findings emphasize the need for early screening and tailored management strategies for childhood astigmatism.